The John Deere L120 is a full featured, riding lawn tractor. The tractor has a tight 18" turning radius and a heavy-duty welded-steel 48" mower which can mulch or bag grass clippings or other lawn debris. There is a seven position cutting height adjuster with a height reminder. Here's a look at some troubleshooting steps if you suspect your cutting-edge piece of equipment isn't working right.
Take a good look at the quality of the cut. If patches of grass are uncut, giving your lawn the appearance of a bad haircut, mow at a slower speed, open the throttle to increase the rpm or clean the mower deck. Raise the cutting height if the blades are scalping the grass. You can also try adjusting the mower wheels and checking the tire pressure. Rough, uneven terrain may also be a cause of scalping.
Check to see if the cut is uneven. This can again be because the mower speed is too fast. It can also be be because of uneven tire pressure, the mower wheels not being adjusted correctly, the deck not level, or the blades are dull. Get the blades sharpened if any of the above steps haven't given you the expected cut.
Check the engine performance. Poor performance is often due to old fuel. That'll be the case if you last season's fuel is in the tank. The nature of the beast is that the mower is going to get dusty and dirty. Check to see dirt hasn't gotten into the fuel filter and clogged it. Does the engine start at all? Remember you need to depress the brake pedal.
Check for electrical issues. Did the battery not charge. Check that the engine speed isn't too slow. Check that the battery cables are clean and worst case scenario--replace the battery.
Check the tractor performance. Too much vibration can be caused by debris on the mower deck or the blades being out of balance. Make sure the blades aren't bent. If the tractor won't move, even though the engine is running-it may simply be because the parking brake is on.